Persistent liver lesions in rats after a single oral dose of polybrominated biphenyls (firemaster FF-1) and concomitant PBB tissue levels.

In a preliminary study, 12 male and 12 female weanling Sherman strain rats were given a single dose of 1000 mg polybrominated biphenyls (PBBs) FireMaster FF1 Lot 7042 kg/body weight as a 5% solution in corn oil. Three male and three female weanling rats were given corn oil. One day after dosing PBB blood levels ranged from 78 to 162 ppm and 42 days later they ranged from 1.1 to 2.99 ppm. The liver was the only organ with pathological changes. In a long-term recovery study groups of 20 male and female rats, 2 months old, were given 0 or 1000 mg PBBs/kg body weight as a single dose in peanut oil. Five rats per group killed 2, 6, 10, and 14 months after dosing had pronounced liver pathology, including hepatic porphyria in the female rats and neoplastic nodules also mainly in female rats. Chemical analyses of blood, liver, and adipose tissue for PPBs 10 and 14 months after dosing gave the following mean results. Blood levels in females were 2.9 and 2.92 ppm, respectively, and males 0.94 and 1.34 ppm, respectively. Adipose tissue levels in females were 1202 and 783 ppm and in males 713 and 866 ppm, respectively. The liver levels in females were 37 and 22 ppm and in males 60 and 63 ppm, respectively.